The experience of Lassen in the bullbospinal poliomyelitis epidemic in 1952 led to general adoptation of artificial ventilation by intermittent positive pressure(IPPV) in the treatment of respiratory failure. The increase in the use of this form of therapy has been matched by an increase in the use of cuffed tubes. This is essential to prevent an air leak during inflation of the lung as well as an aspiration of foreign materials into the tracheobronchial tree. The authors have recently experienced 3 cases of acquired tracheomalacia after endotracheal intubation(tracheal dilatation) and their presenting problems were firstly, the preservation of protection of the lungs and secondly, the danger of respiratory obstruction. Proper procedure for prevention of tracheal damage by cuffs include : cuff volume should be measured each time with a graduated syringe and recorded at least once a week to detect the first signs of dilation.